title: Pro-inflammatory cytokine induction of 11β-hydroxysteroid dehydrogenase type 1 in A549 cells requires phosphorylation of C/EBPβ at Thr235.
abstract: 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts inert glucocorticoids into active forms, thereby increasing intracellular glucocorticoid levels, important to restrain acute inflammation. 11β-HSD1 is induced by pro-inflammatory cytokines in a variety of cells. Here, we show 11β-HSD1 expression in human A549 epithelial cells is increased by pro-inflammatory cytokines (IL-1α/TNFα) via the P2 promoter of the HSD11B1 gene. Inhibition of p38 MAPK attenuated the pro-inflammatory cytokine induction of mRNA encoding 11β-HSD1 as well as that encoding C/EBPβ. IL-1α/TNFα-induced phosphorylation of C/EBPβ at Thr235 was also attenuated by p38 MAPK inhibition suggesting involvement of a p38 MAPK-C/EBPβ pathway. siRNA-mediated knock-down of C/EBPβ and NF-κB/RelA implicated both transcription factors in the IL-1α/TNFα induction of HSD11B1 mRNA. Transient transfections of HSD11B1 promoter-reporter constructs identified the proximal region of the P2 promoter of HSD11B1 as essential for this induction. IL-1α increased binding of C/EBPβ to the HSD11B1 P2 promoter, but this was not observed for NF-κB/RelA, suggesting indirect regulation by NF-κB/RelA. Ectopic expression of mutant chicken C/EBPβ constructs unable to undergo phosphorylation at the threonine equivalent to Thr235 attenuated the IL-1α-induction of HSD11B1, whereas mimicking constitutive phosphorylation of Thr235 (by mutation to aspartate) increased basal expression of HSD11B1 mRNA without affecting IL-1α-induced levels. These data clearly demonstrate a role for both C/EBPβ and NF-κB/RelA in the pro-inflammatory cytokine induction of HSD11B1 in human epithelial cells and show that p38 MAPK-induced phosphorylation of C/EBPβ at Thr235 is critical in this.
authors.affiliation: Endocrinology Unit, University/BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Cristina L
authors.initials: CL
authors.lastname: Esteves
authors.forename: Manu
authors.initials: M
authors.lastname: Verma
authors.forename: Ewa
authors.initials: E
authors.lastname: Róg-Zielińska
authors.forename: Val
authors.initials: V
authors.lastname: Kelly
authors.forename: Shuji
authors.initials: S
authors.lastname: Sai
authors.forename: Amandine
authors.initials: A
authors.lastname: Breton
authors.forename: Francesc X
authors.initials: FX
authors.lastname: Donadeu
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Seckl
authors.forename: Karen E
authors.initials: KE
authors.lastname: Chapman
mesh_terms: D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1 / Q000235:genetics; D042842:11-beta-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000818:Animals; D022782:CCAAT-Enhancer-Binding Protein-beta; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002645:Chickens; D016207:Cytokines / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000276:immunology*; D005938:Glucocorticoids / Q000378:metabolism; D006801:Humans; D008025:Ligases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D022762:CCAAT-Enhancer-Binding Proteins; C545012:CEBPB protein, human; D016207:Cytokines; D005938:Glucocorticoids; D016328:NF-kappa B; D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1; D042842:11-beta-Hydroxysteroid Dehydrogenases; C468386:HSD11B1 protein, human; D008025:Ligases; C028812:guanosine 3',5'-polyphosphate synthetases